Tunnel kiln and draft control for the same



July 12, 1932. A. s. WATTS TUNNEL KILN AND DRAFT CONTROL FOR THE SAME Filed 09?.- 1950 2 Sheets-Sheet 1 I Snventor rffir/rw? .5. 1447775.

BB 1% (Ittomeg July 12, 1932. A. s. WATTS TUNNEL KILN AND DRAFT CONTROL FQR THE SAME 1930 2 sheets sheet 2 w// /z I Patented July 12, 1932 P TENr- TUNNEL KILN AND DRAFT conrnon FOR THE SAME Application filed October 28, 1930. sea-a1 N6. 491,795.

In the drawings:

Figure 1 is a longitudinal vertical section through a tunnel kiln embodying my invention.

Figure 2 is a similar view of a tunnel kiln, the arrows indicating the direction of natural draft from entrance to exit. 7

Figure 3 is a transverse longitudinal View of Figure 2. r

Figure 4 is a vertical longitudinal view of a tunnel kiln with stack at entrance end of kiln, the arrows indicating direction of artificial draft toward the entrance end of kiln.

Figure 5 is an enlarged detail side elevation of a portion of Figure 1.

Figure 6 is a top plan View of Figure 5.

Figure 7 is a Vertical transverse sec ional view of Figure 6 on the line 7-7, Figure 5.

The reference numeral 8 designates a continuous tunnel kiln, having the entrance end 9 and the exit 10. This kiln has a heating up zone 11, a high temperature zone 12, and a cooling zone 13. It will be understood that there may, according to my invention, be one F or more high temperature zones. The natural draft in a tunnel kiln is from entrance to exit as indicated by the arrows 14 in Figure 2. V

In order to carry the draft of heat from the high temperature zones toward the entrance end of the tunnel and thus heat up the ware which is traveling toward the high temperature section of the tunnel, it is customary to provide a stack, or other artificial draft element 15 at the entrance end of the tunnel and thus reverse the natural course of draft travel as indicated by the arrows 16 in Figure 4. This also draws the heat, which is radiated from the ware 18, and conveyors 19, in the cooling end 13 of the tunnel, through the high temperature zone 12, so that all heat not lost by radiation passes over or among the ware being heated up, in the heating up section 11, thus conserving heat. The amount of draft provided will control the rate at which the hot air will travel toward the en-' trance end 9 of the kiln.

The primary object of my invention is to provide means of controlling temperature development and temperature distribution in ceramic tunnel muffle kilns within which the scribe which I have discovered and proven.

The invention provides for the introduc lllOIlOI a blast of air from below or atthe ARTHUR s. WATTS, or COLUMBUS, am 7 sides of the cars 19 or other conve in dea 7 s g vices, into the area above the conveying devices 19 on which the ware is carried, the

said blast of air being projected bythe'air blast device 20, connected with the com pressed air line 21, into, the currents of air (see arrows 16) induced by-thestack 15,0r

otherart iiicial draft, and toward theentrance 9 of the tunnel. Thisacts as acounter-draft and damperto the natural draft and accel crates the artificial draft, and causes the heat .yond the. point ofentrance of said draft of air and toward the entrance end of thekiln. I also provide for the introduction of a blast of air, bymeans of the air blast22, on

a level with or above the level of thetop of the car, or other conveying device 19, the said blast of air being directed toward the entrance end'of the kiln so that the natural draft which travels from the entrance end through the high temperature zone, or zones, and toward the exit end of the tunnel is nullified, and the temperature developed in the high temperature zone isprevented from traveling toward the outlet end of the tunnel and by a proper control, .by valve 23, of n the amount-of air blast orcounter-draft provided the heat is banked up'in the high temat right angles to the line of travel of the ar- 1 t tificial and natural drafts, and by thus diverting a limited portion of the heat existlng between the point of entrance of the blast 24 and the ventilator, a zone of heat from the high temperature zone beyond this temperature drop is regulated.

The high temperature zones are provided with muflie walls-27. The air blast 20 is controlled by the valve 28.

I do not claim the apparatus herein shown for settingup a draft longitudinally in the kiln counter to the naturaldraft from the entrance end of the kiln as that is the invention of Homer A. Evans, who has filed anapplication for patent thereon, Serial No. 4:91,- 793, In invention consisting in utilizing the Evans invention in combination with the v auxiliary ventilator and blast 24, whereby a zone of lower temperature is developed and d the penetration of'heatfrom a hightemp'erature' zone; beyond this temperature drop is regulated.

WhatI'claim is: I,

1. Ina tunnel-kiln consisting of a heating up zone, high temperature .zones, and a cooling zone, through which ware travels, and an artificial draft element, an auxiliaryventi- 'lator'forjthe tunnel between the high tempelrat'ure zone and the entrance of the tunnel,

' trance of thebla'st and ventilator whereby means to create a draft through the tunnel into said auxiliary ventilator and at substantially right angles to the line of travel of the artificial and natural drafts of the tunnel thereby diverting a limited portion of heat existing between the point of ena zone of lower temperature isdeveloped and thepenetration of heat from a high temperaturejzon'e beyond this temperature drop is regulated '2. "In a tunnel kiln consisting of a heating up zone, high temperature zone, and a cooling zone, through which the ware travels, an artificial j draft element at the entrance en'd'of't'h'e tu'nnehmeans for controlling 'temv pjerature development and temperature distribution in said tunnel including an air blast element to project air blasts into the currents of air induced by the said artificial draft toward the entrance of the tunnel to cause the airto bank up within a limited area and develop an abrupt I temperature drop beyond the point of entrance'of said draft of air and toward the entrance end of the tunnel, an air blast element fordirecting a bla st ofai-r towardthe entrance end of the tunnel to nullify the natural draft which travels from the entrance end toward the exit end of j the tunnel, an auxiliary ventilator for the tunnel between the high temperature zone :and the entrance end of the tunnel, but at 'a-point nearer the high temperature zone than the said artificial draft element, and an airfblast element to introduce an'air blast into the'tunnel 'a'tright angles to the l-ine'of travel 

